325
FXUS65 KTFX 100815
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
215 AM MDT THU SEP 10 2026
KEY MESSAGES
- WARM, DRY AND BREEZY TODAY.
- NEXT WEATHER SYSTEM ARRIVES FRIDAY, BRINGING COOLER
TEMPERATURES ALONG WITH SOME PERIODS OF RAIN/MOUNTAIN SNOWFALL.
- ANOTHER WEATHER SYSTEM BRINGS EVEN COOLER TEMPERATURES AND
MORE WIDESPREAD PRECIPITATION TO MONTANA, WITH MORE CHANCES FOR
MOUNTAIN SNOWFALL.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
IN THE WAKE OF A SERIES OF UPPER LEVEL SYSTEMS EARLIER THIS WEEK,
A WEAK RIDGE EMBEDDED IN NORTHWESTERLY FLOW WILL CONTINUE TO
BRING A PERIOD OF WARMER BUT BREEZY WEATHER TO NORTH CENTRAL
MONTANA TODAY. THIS PERIOD OF WARMER WEATHER WILL COME TO A QUICK
END ON FRIDAY AS A DECAYING UPPER LEVEL TROUGH MOVES THROUGH
SOUTHERN BRITISH COLUMBIA AND ALBERTA INTO MONTANA, WHICH WILL
BRING COOLER TEMPERATURES, ALONG WITH SOME SHOWERS OF RAIN AND
MOUNTAIN SNOWFALL AS IT PUSHES THROUGH. THE COOLER TEMPERATURES
WILL LINGER BEHIND THIS SYSTEM, WHICH WILL SET UP THE NEXT,
STRONGER SYSTEM TO PRODUCE WIDESPREAD PRECIPITATION WITH SNOW
EXPECTED ABOVE 7000 FEET, WHICH WOULD INCLUDE SOME OF THE HIGHER
MOUNTAIN PASSES.THE UNSETTLED WEATHER PATTERN WILL CONTINUE INTO
EARLY NEXT WEEK, WITH CONTINUED CHANCES FOR RAIN AND MOUNTAIN
SNOWFALL.
- FORECAST CONFIDENCE & SCENARIOS:
WINDS TODAY: WESTERLY, CROSS BARRIER FLOW WILL BRING SOME GUSTY
WINDS TO NORTH CENTRAL AND SOUTHWESTERN MONTANA TODAY. WHILE WINDS
ARE NOT EXPECTED TO BE STRONG ENOUGH TO REACH HIGH WIND CRITERIA
(58 MPH FOR MOST, 75 MPH ALONG THE ROCKY MOUNTAIN FRONT), GUSTS TO
35-50 MPH WILL BE POSSIBLE ACROSS THE AREA, ESPECIALLY ALONG THE
ROCKY MOUNTAIN FRONT AND NORTH SLOPES OF THE LITTLE BELTS, WHERE
WINDS WILL BE STRONGEST.
MOUNTAIN SNOWFALL THIS WEEKEND: A STRONG UPPER LEVEL LOW WILL MOVE
INTO THE TREASURE STATE OVER THE WEEKEND, BRINGING WELL BELOW
AVERAGE TEMPERATURES ALONG WITH COPIOUS AMOUNTS OF MOISTURE. THE
COOLER TEMPERATURES WILL BRING SNOW LEVELS DOWN TO 7000 FEET ABOVE
SEA LEVEL, WHICH WILL RESULT IN WIDESPREAD MOUNTAIN SNOWFALL TO
AREAS ABOVE 7000 FEET. CURRENT FORECASTS KEEP SNOWFALL AMOUNTS
UNDER 6 INCHES AT THE MOMENT, BUT SOME OF THE HIGHEST TERRAIN
STILL HAVE AROUND A 10 PERCENT CHANCE OF SNOWFALL AMOUNTS OVER A
FOOT OVER THE WEEKEND. LUDWIG
AVIATION
10/06Z TAF PERIOD
HIGH CONFIDENCE IN VFR CONDITION ACROSS ALL TERMINAL THROUGH THE
TAF PERIOD. I ADDED LLWS TO THE PREVAILING GROUPS FOR TERMINALS
KCTB AND KHVR AS MODEL SOUNDINGS AND SURFACE OBSERVATIONS CONTINUE
TO SUGGEST BOUNDARY LAYER DECOUPLING IS ONGOING LEADING TO STARK
DIFFERENCES BETWEEN SURFACE AND 2KFT WINDS. BREEZY CONDITIONS
WILL BE THE THEME THROUGH MUCH OF THE DAY ESPECIALLY ACROSS NORTH
CENTRAL MONTANA. WIDESPREAD WIND GUSTS OF 20-35KT ARE EXPECTED
AREA WIDE, WITH TERMINALS KCTB, KGTF, AND KHVR LIKELY SEEING GUSTS
ON THE UPPER END OF THAT RANGE. WINDS WILL REMAIN THROUGH THE
PERIOD, ONLY LIGHTENING UP TOWARDS THE IMMEDIATE END. -JR
FOR KGTF: ODDS OF LLWS HAS DROPPED FROM THE PREVIOUS DISCUSSION AS
MIXING HAS PROVED EFFICIENT AT KEEPING SURFACE WINDS UP. WINDS
WILL AGAIN RAMP UP INTO THE AFTERNOON WITH A SLIGHTLY MORE
FAVORABLE SOUTHWEST DIRECTION (220-230 DEGREES) THROUGH 10/18Z
WHEN PROBABILITY OF CROSSWIND CRITERIA EXCEEDANCE IS LOW (30%).
FOLLOWING THAT, WINDS WILL BECOME MORE WESTERLY (250-270 DEGREES)
AND CONFIDENCE IN BOTH CRITICAL SUSTAINED AND GUST CROSSWINDS
RISES GREATLY TO >60%. AS WE NEAR THE END OF THE TAF PERIOD WINDS
WILL BECOME WEAKER WHILE MAINTAINING THE WESTERLY COMPONENT THUS
THE RISK OF 15KT CROSS WINDS DECREASES BUT STILL REMAINS HIGH
ESPECIALLY WITH ANY SPORADIC GUSTS.-JR
PRELIMINARY POINT TEMPS/POPS
GTF 81 48 59 43 / 0 80 60 10
CTB 73 42 54 39 / 0 50 80 10
HLN 84 50 68 46 / 0 70 60 0
BZN 84 48 73 44 / 0 0 10 10
WYS 72 36 72 31 / 0 0 10 0
DLN 82 46 77 40 / 0 0 0 0
HVR 82 45 64 38 / 0 40 70 0
LWT 84 45 60 39 / 0 50 90 20
TFX WATCHES/WARNINGS/ADVISORIES
HTTP://WWW.WEATHER.GOV/GREATFALLS
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